Overweight and obesity are costly and prevalent public health problems facing the majority of Americans. Being overweight or obese is related to heart disease, stroke, metabolic syndrome, and other deadly consequences. Barriers to receiving traditional weight loss treatment with a therapist include cost, time, and accessibility.A place to intervene may be at individuals' primary care provider appointments. Unfortunately, most primary care providers are busy and may not have the time or resources to provide treatment. Therefore, it is important to design and test effective weight loss treatments that do not require extensive training or time. As such, the internet has extensive public health potential for widespread dissemination of behavior change tools and interventions for weight loss. Internet-based treatment outcomes can be further improved by incorporating clinician support for weight loss, the use of online programs, and individualized feedback. The purpose of this application is to address overweight and obesity by testing an easily accessible weight loss treatment that can be provided in primary care centers (PCCs). The first aim includes a treatment approach that combines two recently developed weight loss treatments that received initial empirical support relative to Usual Care (UC) in a K23-funded randomized controlled trial (RCT). In the proposed study, patients will receive both Nutrition Psychoeducation (NPC) and Motivational Interviewing (MIC), supplemented by the internet for 12 weeks, to determine outcomes associated with this conceptually synergistic combination (NPC+MIC). Treatment will be provided by medical assistants; this method of delivery is intended to increase generalizability to other PCCs. Patients will be comprehensively assessed at baseline, post treatment, and at 3-month follow-up. It will be important to test MIC and NPC combined, as NPC+MIC may lead to even more weight and weight-related changes. The feasibility, however, of combining these treatments requires empirical examination. The study will provide needed empirical information about a scalable and potentially effective weight loss option for primary care offices. Patients receiving NPC+MIC are hypothesized to experience significant weight loss and improvements in metabolic variables and mood. The second aim is to compare the NPC+MIC outcomes to those from the completed K23 RCT study that compared UC to two internet supplemented treatments, NPC or MIC alone, provided in primary care by medical assistants. The current application addresses limits of the treatment literature by including free and easily accessible internet support, patients who are overweight and obese, metabolic syndrome, patients with binge eating disorder, treatment clinicians available to many PCCs, assessment of treatment fidelity, and follow-up assessment after a period of treatment cessation. The outcomes for patients receiving NPC+MIC are hypothesized to be significantly better than for those who received NPC alone, MIC alone, or UC in the K23 RCT.